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Abstract

Purpose: Combination therapy with the female hormones estrogen (E) and progestins are very frequently used with approximately 100 million women worldwide taking oral contraceptives (OC). Recent trials have cast doubt on the cardiovascular safety of hormonal replacement therapy (HRT). In contrast to the HRT-controversy, little attention has been focused on OC, a therapy using 10 –100 fold higher levels of E than HRT. We describe population correlates of long-term OC use.

Methods: The Asklepios study is a representative sample (2524 M/F volunteers, 35–55 years) from the Belgian general population free from overt cardiovascular disease. Vascular echography of the carotid and femoral arteries was systematically performed and atherosclerosis was defined by presence of carotid or femoral plaque.

Results: Of 1301 women (median age 45.7 y), 27.4% were taking OC and 10.0% were taking HRT. In contrast, past OC-use is far more prevalent: 81% of women having taken OC for at least 1 year, with a median exposition of 13 years. After multivariate adjustment for age, smoking, blood pressure, lipids, obesity, diabetes, physical activity, fruit, vegetable and alcohol intake, educational level and drug therapy (lipid-lowering, antihypertensive, aspirin), use of OC was associated with a significant increase in carotid or femoral unilateral plaque. Odds ratio’s (OR) per 10 years of OC exposure were: carotid plaque 1.17 (1.00 –1.33) and femoral plaque 1.28 (1.10 –1.47). We also looked at prevalence of bilateral disease (involvement of right and left carotid/femoral artery) as a more stringent phenotype of atherosclerosis. OR per 10 years OC exposure were: carotid plaque 1.42 (1.03–1.84); femoral plaque 1.34 (1.05–1.63).

Interpretation : Use of contraceptive therapy is very common and associated with an unexpected increase in the prevalence of carotid and femoral atherosclerosis in otherwise young, apparently healthy women. Our data suggest a 20 –30% increased prevalence of plaque in the carotid and femoral arteries per 10 years of OC exposure. In the light of widespread (>80% of our population sample; > 100 million women globally) and usually prolonged OC use (>10 years) these results suggest OC use could be an important factor in the global atherosclerotic burden.